Engine cooling monitoring - Automobili Lamborghini Holding Spa ...

OBD DescriptionOBD Group ANL-VIssue date: Sep/08Test Group – ANLXV06.5474 Revision date: rev 1.0 of 22/10/2008Engine cooling system monitoring_____________________________________________________________________________________________________________Automobili Lamborghini s.p.a. OBDII – MY 10 Section 10 Page 1

OBD DescriptionOBD Group ANL-VIssue date: Sep/08Test Group – ANLXV06.5474 Revision date: rev 1.0 of 22/10/2008Thermostat Monitoring_____________________________________________________________________________________________________________Automobili Lamborghini s.p.a. OBDII – MY 10 Section 10 Page 2

OBD DescriptionOBD Group ANL-VIssue date: Sep/08Test Group – ANLXV06.5474 Revision date: rev 1.0 of 22/10/2008Basic Theory and algorithm_____________________________________________________________________________________________________________Automobili Lamborghini s.p.a. OBDII – MY 10 Section 10 Page 3

OBD DescriptionOBD Group ANL-VIssue date: Sep/08Test Group – ANLXV06.5474 Revision date: rev 1.0 of 22/10/2008Lamborghini engines are equipped with a thermostat to control the engine coolant circuit.When the thermostat is closed the engine temperature is function of the fuel flown to the engine. Inthat condition the amount of heat from engine cooling system to the air can be ignored (if the thermostatis closed, no water flows to the radiators) and the temperature of the cooling liquid depends only on howmuch fuel has been burnt in the engine.Under that premise, a mathematical model of the temperature characteristic vs the fuel injected in theengine has been built, and a function which calculates the amount of fuel injected in the engine has beenadded to the engine management software. From this mathematical model an estimated engine coolanttemperature is calculated.According to the requirements in CARB “§1968.2. Malfunction and Diagnostic SystemRequirements--2004 and Subsequent Model-Year Passenger Cars, Light-Duty Trucks, andMedium-Duty Vehicles and Engines” Section (e) (10.2) the thermostat is considered malfunctioning ifthe coolant temperature has not reached 70°C (highest temperature required to enable the otherdiagnostics of the Lamborghini OBD II System) when the modeled coolant temperature has reached thevalue of 75°C.In compliance with CARB requirements, Section (e) (10.2.1) monitoring is inhibited if coolanttemperature at cranking is lower than –7°C. The monitoring is also inhibited when engine coolanttemperature at cranking is above 50°C to avoid false passes. Otherwise, the monitoring system operatesonce each driving cycle._____________________________________________________________________________________________________________Automobili Lamborghini s.p.a. OBDII – MY 10 Section 10 Page 4